Process of making paint.



UNITED STATES PATENT OFFICE.

HEINRICH I-IAOKL AND HUGO BUNZEL, OF HEUFELD, GERMANY.

PROCESS OF MAKING PAINT.

No Drawing.

To all whom it may concern.-

Be it known that we, Hammer! HacitL, a subject of the Emperor of Austria-Hunary, and H000 BUNZEL, a subject of the ing of Prussia, and residing both at Heufeld, Upper Bavaria, Germany, have invented certain new and useful Improvements in Processes of Making Paint; and we do hereby declare the following to be a full, clear, and exact description of the invention.

This invention relates to the manufacture of yellow to brown pigments from sullld of iron.

I-lerctofore it has not been possible artificially to make yellow to yellowish brown pigments which could replace natural ocher with regard to purity of color, body, stability in oil and low price. It is true, that the yellow basic sulfates of iron are of a pure color, but they ossess no body and change in color in oi. Hydrates of iron precipitated in the usual manner from solutions of ferric salts by means of hydroxids and carbonates are brown and flaky and these dry in the form of hard pieces. Titanate of ferric oxid or ferric titanate obtained by roasting is more expensive to manufacture than natural ocher. This last example also shows how great the demand is to make a. product equivalent to natural ocher. These considerations have led to the resent invention which is based on the idea that between red ferric oxid of good body and hydroxids which are rich in water and of poor body there must be yellow hydrates containing but little water and similar to ferric oxid with regard to its properties as a pigment. \Ve have found that by introducing a solution of a ferric salt or of a ferrous salt, into a solution of an alkali metal sulfid or of an alkali earth metal sulfid, we can produce a hydrated sulfid of iron, and we can produce, by oxida: tion of said precipitate with air, an iron hydrate which possesses all the properties above mentioned so largely that natural ocher is excelled whether the sulfur is removed from the hydrate or not. As the purity of the color tone depends, of course, on the purity of the sulfid of iron it is important to make the latter from pure materials. Therefore neither crude gas-purifying mass nor the same purified from cy- Speeltleatien of Letters Patent.

Application flied March 18, 101. Serial No. BMADX.

Patented Mar. 1-1, 1910.

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The hydrated sullid of iron thus obtained is oxidized in a suitable vessel by treatment with air and the mixture consisting of ferric hydrate and sulfur is filtered and washed. The sulfur may be removed by known solvents, such as bisullid of carbon, for example, or it may remain in the product. The precipitate freed in a suitable manner from adhering water forms the finished pigment. Its color lluctuatcs between yellow and yellowish brown and is determined largely by the temperature at which it was ()XltllZOt. Its covering power or body and fineness considerably excel those of natural ocher. The pigment thus produced is thereafter mixed with a suitable vehicle (such as oil, above referred to) in the usual or any approved manner, to produce a mint.

\Ve claim as our invention:

1. A process of producing a paint, which comprises subjecting hydrated sulfid of iron, in the presence of moisture, to atmospheric oxidation, to produce a material containing ferric hydrate suitable for use as a pigment, and mixing the same with a paint vehicle.

2. A process of producing a Joint which comprises subjecting hydrated sullid of iron, to atmospheric oxidation to produce a )igmcnt containing ferric hydrate, removing free sulfur from said material, by subjecting said material to the action of a sol\' cut for sulfur, and thereafter mixing the same with a paint vehicle.

8. A process of making a paint which comprises adding a solution of an iron salt iii:

to a soluble sulfid, to precipitate a hydrated names to this specification, in the presence iron sulfid, and subjecting said precipitate of two subscribing Witnesses.

in the presence of moisture, to atmospheric HEINRICH HACKL. oxidation, to produce a pigment containing HUGO BUNZEL.

C ferric hydrate, and thereafter mixing said Witnesses:

pigment With a paint vehicle. A. W. VOIGT,

In testimony whereof We have signed our ARTHUR GUBE. 

